<VV> Re: Try Overdrive

[mark at noakes.com]

I have one of the BW units to go into my 58 Suburban when it's done to 
replace the plain 3 speed...not sure how you would ever adapt that to a 
Corvair...

http://blog.mark.noakes.
com/blog/Vehicles/58Suburban/_archives/2006/3/18/1827003.html

I may have calculated wrong but I was thinking that this would drop me 
down from a 3.90 to a 2.73 and yes, I was thinking about using it as a 
OD/4th gear and not as a split shift as you mention.

Mark Noakes

----Original Message----
From: FrankCB at aol.com
Date: Feb 15, 2007 11:00 
To: <kwoodke at comcast.net>, <virtualvairs at corvair.org>
Subj: Try Overdrive  Re: &lt;VV&gt; 4Speed Powerglide?

 
Keith,
    Reminds me that one of the reasons I bought my 1951  Hudson Hornet 
(in 
1955) was the Borg Warner overdrive that supplemented the "3  on the 
tree" 
(stock 3 speed manual transmission).  The BW unit was  added to the 
end of the 
stock trans and had a planetary gear set that gave,  in effect, 2 
additional 
speeds to the stock 3 speed trans.  While most  people used the 
overdrive (about a  
0.7 ratio) as a simple 4th gear to  reduce the engine speed for 
cruising (it 
gave about 2.9 overall ratio), I also  used it when I was in 2nd gear 
especially when merging onto a major  highway.  The BW o'drive was 
semi-automatic, so 
while merging, if  necessary for a sudden major increase in 
acceleration, I 
would simply  "floor" the accelerator.  This instantly "kicked down"  
the 
o'drive gearset from 0.7 to 1 moving the gearing combination from 2nd  
gear PLUS  
o'drive to plain 2nd gear with a good increase in rpm  and pickup.
    The BW o'drive could be locked out  of operation (using a lever 
under the 
dash) thereby giving  just a straight 1:1 ratio useful in driving on 
steep 
hills.  In addition,  since it had an overrunning clutch inside, it 
also allowed 
clutchless shifting  (within certain limits).  Of course, as an 
inveterate 
"changer", I had  to add my own switch so I could "drop out" of 
o'drive without 
flooring the  accelerator pedal.
    All in all, it was a GREAT device and I'd love to  see somebody 
figure 
out how to install one on the end of a Corvair manual  OR PG 
transmission.  On 
the PG it would give, in effect, 4 forward  gears:  1.8, 1.3, 1.0 and 
0.7.  
With the normal 3.55 rear,  it would drop the overall ratio in top 
gear to about 
2.5 and the rpm at 70 mph  from 3500 rpm to about 2500 rpm.
    Frank "stock is a good BEGINNING"  Burkhard